The study found that managers are most likely to grant a request to men in high-status jobs in order to pursue career advancement opportunities like professional development classes, while women in the same job making the request for the exact same reason weren’t as likely to get approval. The researchers explained the preference for giving men flexible time for career development by pointing to “the greater respect and admiration managers felt toward high-status male employees to high-status female employees.”

While authors Victoria L. Brescoll, Jennifer Glass, and Alexandra Sedlovskaya had expected to find that men would be less likely to be granted flexibility for childcare reasons, they didn’t find anything supporting that idea. In fact, men in low-status jobs who asked for flextime to care for children were more likely to have their request granted than high-status men, while for women, neither their job status nor their reasons impacted managers’ decisions about whether to grant the request.

The authors also note that the results are likely a conservative look at the differences between genders when it comes to these requests, as they only studied a shift in work hours, not a reduction, which might have a greater negative impact. They also focused on a gender-neutral occupation, but it is likely that managerial bias would be higher in more gender segregated jobs.

Most American workplaces either have no official policy on flexible scheduling or have policies that specifically protect managerial discretion in granting requests, the report notes. Federal labor law also leaves such negotiations to the discretion of supervisors. Therefore, most workers have to ask for permission, putting female employees at a disadvantage under the report’s findings.

More parents are requesting flexible work arrangements as they seek to balance their jobs with their families. Half of both working mothers and fathers report that they find it difficult to balance those responsibilities. And employer surveys show that a growing number have employees in alternative work arrangements.

The U.K. and the European Union both have enacted legislation that grants employees the “right to ask” for schedule accommodations. But the U.S. is an outlier in its lack of policies. As the report notes, “In contrast to most developed nations, the United States stands nearly alone in its reliance on the free market to set work hours and work schedules among employees in both the public and private sectors.”

Yet the idea has cropped up on this side of the Atlantic. San Francisco is the first place in the U.S. to consider such a law with a recent ballot measure on it introduced last month.